Friday, March 30, 2012

[BTW, I'm still dictating these blogs using Dragon NaturallySpeaking. I'm trying to be alert for typographical errors caused by the software, but if you are still slipping by. I will have about a week between the time I wrote this blog, and the due date for the next blog. Hopefully medication and therapy will allow me to get back to typing by that time.]

Brain machine interfaces are important not just for "bionics" but also for interfaces that would allow quadriplegics and those with neurodegenerative diseases to interface with the outside world. One of the key questions in developing a brain machine interface is: What is the nature of the information that is to be interfaced? With sensory information such as been discussed in the two previous blogs, we need to know two things: (1) how much information do we want to input to the brain, and (2) what pattern does the brain expect to see? With the visual and auditory prosthetic discussed in Monday's blog, researchers and doctors utilize residual neural function in the eye and ear, respectively, and simply provide a pattern of electrical stimulation that is "mapped" in a manner similar to the normal input to retina or cochlea. Tactile and proprioceptive sensation, as required for an effective bionic limb, is a little bit more complex, since the inputs will likely need to be transmitted directly to the appropriate area of the brain that normally receives input from limbs. Likewise advanced improvements in visual and auditory prosthetics – the degree of sophistication required to truly replace sight and sound – will also need to provide inputs directly to the visual and auditory processing regions of the brain.

This problem is already being faced by the researchers working on the Revolutionizing Prosthetics program by DARPA, and that direct brain control of motor movements also necessitates interfacing with the part of the brain that normally controls muscles. Both of these problems require a means of either transmitting any electrical stimulus directly to the brain or reading the brains electrical activity and translating it to an external device. in many ways this is a separate field of neuroscience, termed Brain Machine Interfacing.

Brain Machine Interfacing, or BMI, is a field with two major goals: (1) understanding the normal brain "code" that corresponds to sensation, movement, memory, or any other cognitive function; (2) providing an appropriate "interface" between neurons and electronics. In many ways part one of BMI is no different from any of the studies of neuroscience, in which we try to better understand the functions of the brain. However, the particular goal of BMI with understanding the brain is to be able to point to specific patterns of neural activity and say "this represents an input" or "this represents a memory."

"Utah array" http://www.sci.utah.edu/~gk/abstracts/bisti03/

The second half, or second challenge, of BMI is, in many ways, much harder even though it would seem to be the simpler problem. The type of electric is commonly used for recording neural activity is simply a wire – insulated along its length, with only a small area exposed at the tip. Sharpened tungsten electrodes may have an exposed surface of less than a micron, while stainless steel, nichrome, or platinum iridium wire, typically have surface areas of about 20 to 50 square microns. Since the diameter of a single neuron is itself about 20 square microns, one would think that these electrode sizes would be adequate for recording single neurons. In fact, the larger surface area of non-sharpened electrodes is more appropriate for recording multiple neurons, requiring software that can separate the activity of more than one neuron. While smaller diameter electrodes would seem to be more precise, and more accurate, they do not remain effective as long as non-sharpened electrodes. The major problem with this type of electrode is that either the wire or the brain tissue itself can move reducing the effectiveness of the electrode. Another problem is that the glial cells which provide metabolic support to neurons will tend to encapsulate and insulate foreign objects in the brain. When this happens to electrode its ability to record neural activity is decreased and eventually eliminated.

"Michigan arrays" by NeuroNexus

A much more recent approach is to develop recording electrodes that resemble printed circuits, with recording surfaces, and structural materials, that are inert. Silicon and ceramic substrates, with printed platinum "wiring" provide many advantages for BMI. In the first place, silica and ceramic and platinum are much less likely to cause inflammation and gliosis. In the second place, the "printed circuit" process allows manufacture of patterns of electrode-like recording sites arranged in grids that can stimulate many neurons in many different areas and and provides many orders of magnitude more information to be either recorded or stimulated. The "Utah Array" (http://www.sci.utah.edu/~gk/abstracts/bisti03/) shown above is one such array, while the "Michigan Arrays" (http://www.neuronexustech.com/) shown at left represent a more classic printed circuit approach. It is still the case that implanted electrodes have a finite duration of function. We still don't know entirely how long electrodes of this type will remain functional when implanted into the human brain. Even the patient's who will be working with the "bionic" arm prosthesis, will only have electrodes implanted into the brain for a few years. Research is ongoing to determine what is the "best" type of electrode that can be implanted once and remain functional for the lifetime of the patient.

The field of neural prosthetics requires a number of developments before we can reach the goal of true "bionic" prosthetic organs and limbs. In addition, creation of "cyborgs", or cybernetic organisms, is even further in the future, requiring great advances in interfacing between the brain and external devices. In the next blog, I will finish this series on advanced prosthetics, bionics, and brain machine interfaces with the discussion of techniques for interfacing brains and computers by means of "reading" brain activity without electrodes implanted in the brain.

Until next time, take care of your brain. It's better than a poke in the eye with a sharp… electrode!

Wednesday, March 28, 2012

The post on Bionics and Brain Machine Interfacing will be divided into two parts. Part of this it's because of my ongoing difficulties with carpal tunnel syndrome, any other part is to accommodate some professional travel in which I will actually be working on a related project.

In the previous blog, we discussed the state-of-the-art in visual and auditory prosthetics. Were still a long way from the ideal of The Six Million Dollar Man, and that these prosthetic devices are not yet fully integrated with brain inputs, and cannot completely replace the role of the natural sensory organs. In many ways the science of Bionics, or more accurately neural prosthetics, is still quite primitive and will remain so until several very important factors are resolved. These problems are, in no particular order, complexity of the signals that have to be interfaced with the brain, longevity of the electrodes then need to interface with the brain, complexity of the prosthetic (such as number of pixels in the visual field, or the multitude of movement possible at a single joint), powering the prosthetic, and weight of the prosthetic.

The issue of complexity is made rather obvious from the fact that current visual and auditory prosthetics are unable to render the rich diversity of sight and sound – however this is primarily an issue for density of receptor and stimulation electrode. However when it comes to artificial limbs, there are many factors that must be considered: how many joints, the directions those joints can move, movement of joints in synchrony, and coordinating all of those movements. The problem of appropriate electrodes to interface a prosthetic with the brain is one that will actually be covered in Part Two of this blog which will specifically involve interfacing the brain with external devices.

"The Six Million Dollar Man", Harve Bennett Productions, 1974

Some rather astounding work has been accomplished in the past five years that address the remaining factors, particularly with respect to developing a brain operated upper limb prosthetic – in other words, a bionic arm. I have previously mentioned the defense research agency DARPA, which is considered by many to essentially fund "science fiction". In 2007 DARPA funded a project called Revolutionizing Prosthetics. The goal of the program was to develop a brain interfaced upper arm prosthetic, essentially similar to the Six Million Dollar Man prosthetic shown in this picture. One of the principal goals of this project was to develop a "bionic" limb that was capable of complex emotions such as flexing fingers and rotating the wrist, yet was no heavier than a limb made of flesh and blood. The original project in 2007 funded a company by the name of DEKA, founded by Dean Kamen, inventor of the Segway. The project was quite successful, and resulted in a follow-up program which began in 2009, to begin the first tests of interfacing the prosthetic with the brain, culminating in the first patients by 2013. This is a multi-institutional research project, spearheaded by Johns Hopkins University, and involving at least 10 other universities and a similar number of foundations and private companies. The following website provides a short summary of the program (http://www.neurotechreports.com/pages/darpaprosthetics.html), and many of the reports from DARPA can be found in a Google search. Just used keywords "revolutionizing prosthetics".

One question that may be asked at this point, is why the prosthetics program is concentrating on an upper limb or arm and hand prosthetic, and not a lower limb leg and foot prosthetic. A major reason is that at present brain control is not necessary for effective prosthetics for lower limbs. Biomechanical devices that utilize springs and pistons are quite capable of mimicking lower limb function provided some residual portion of the leg below the hip is present. Note that even these biomechanical limbs still meet the definition of "bionic" or lifelike as first defined by Dr. Jack E Steele in the 1950s. The next revolution in lower limb prosthetics will be to provide self motivating legs to replace total amputation from the hip. However the complex motions required to lift, twist, handle, and manipulate objects as required by fingers, wrists, and elbows has placed current emphasis for bioelectronic prosthetics on the upper limb.

With all of the wonderful progress that's being made on prosthetics with this program, a major hurdle is still providing sensory feedback from the limb to the brain. In many ways this becomes a problem very similar to advanced visual and auditory prosthetics. Several of the teams funded by the Revolutionizing Prosthetics program are working on precisely the issue of providing both tactile and proprioceptive feedback. Again, this is largely an issue of interfacing with the brain, which I will address in the next blog.

Monday, March 26, 2012

As some of you may know over the past several years I've been working in the field of neuroprosthetics. this field has seen a number of startling developments just in the past five years. While auditory prosthetics, in the form of the cochlear implant, have been around for more than 20 years, we have yet to come up with a similar prosthetic for the eye. However as I reported last June, much progress has been made with the Argus 2 device by Second Sight.

The cochlear implant consists of microphone connected to a processor that selects and enhances waveforms associated with speech. This processor then activates electrical stimulation within the cochlea of the inner ear. In this manner, nonfunctioning structures which may include the eardrum and ossicles (small bones which translate vibrations of the eardrum to movements of the fluid inside the cochlea), are bypassed. However this prosthetic requires that the cochlea be intact with normal neural function connecting to the brain.

Likewise the Second Sight retinal prosthetic requires intact neurons in the retina, but can bypass faulty cornea, iris, lens, and photoreceptors. The Argus 2 collects input images from the camera, processes to enhance black and white images and edges, and converts the image to single pixels that are then represented as stimulation to discrete retinal ganglion cells. Like the artificial cochlea, it requires that the normal neural connections into the brain are intact. Neither of these devices can replace a missing or totally damaged ear or eye, much less replace the function of damaged brain structures subserving those sensory functions.

"The Six Million Dollar Man," Harve Bennett Productions, 1974

Sadly we are not yet at the level of full "Bionics" as portrayed in Steve Austin, "The Six Million Dollar Man" (which is itself an adaptation of a character created by author Martin Caidin in his 1972 novel Cyborg). While Caidin's protagonist essentially only had a camera in a glass eye, and not the fully integrated prosthetic of the TV show (right), the novel utilized the basic principles of interfacing prosthetics directly actually neural tissue, leading Caidin to adopt a term invented by Dr. Jack E. Steele in 1958: "bionic" (from the Greek bion, meaning "unit of life" and the suffix -ic, meaning "like" or in the manner of; hence, "life-like"). The term conveniently adapted to the rise of computers and electronics, and is commonly associated with biological and electronic, and has the advantage of not evoking quite the horror movie fright as the alternate term "cyborg" (cybernetic organism).

The current state of the art in retinal and cochlear prosthetics certainly restore at least a portion of the ability to see and hear. However, they are highly dependent on microcomputer processors which take an image or a sound and reduce it to very simple elements before transmitting the stimulus to the residual neural tissue in an existing retina or cochlea. The Argus I retinal stimulator produced only a 4 x 4 matrix of stimulation - only 16 spots on the retina could be stimulated, and the only images that could be detected were light, dark and edges. The Argus II stimulates an 8 x 8 grid, with newer designs of 100 and 1000 total "pixels." And yet, patients with an Argus II are able to read - one letter at a time - presented full size (>15 inches) on a computer screen. When the difference is total blindness vs. one letter at a time, it is a highly significant difference. Likewise, sound transmitted to a cochlear implant is filtered and preprocessed to remove background sound and enhance the frequencies and tone of human speech. In speaking with a person who has had an implant since a young age, you encounter none of the distortion of pitch and tone normally associated with the speech of a nonhearing person - much the same as when speaking with a person who lost their hearing as an adult. However, the preprocessing for speech has its price: cochlear implant is inadequate at reproducing music or subtle background sounds of nature. In addition, the preprocessor can overload in "party" settings, with too many overlapping voices to effectively isolate single conversations. Yet again, this auditory prosthetic is a significant advance over no hearing at all.

So what would it take to have a "real" neural prosthetic that directly interfaces with the brain as in the picture above? The answer to that question can be found in the next installment of The LabRats' Guide to the Brain in which we examine Bionics and Brain-Machine Interfaces!

Friday, March 23, 2012

In the previous Guide blog, I discussed to diabetes in the brain. One of the follow-up comments requested a discussion diabetic neuropathy. So before moving onto the next topic - by special request: today's Guide blog is on Diabetic Neuropathy.

Copyright O2Creationz, 2012
Used under license from Shutterstock.com

As previously mentioned, neurons in the brain are not dependent on insulin for their uptake of glucose from the blood. This is not to say that neurons are insensitive to insulin or that insulin has no effect on neurons. In fact, we are still discovering the many effects of insulin in the brain, and it may very well be the case that insulin has a beneficial effect in glucose uptake, it's just that insulin is not necessary at low levels of activity. Thus, in the brain the effects of high blood glucose are largely due to the osmotic properties of the glucose molecule dissolved in the liquid component of blood. In this manner, glucose acts very much like high salt concentrations. It is fairly well known that one means of preserving food is to dehydrate it, quite frequently with salt. High salt concentrations draw water out of the cells, and prevent contamination or spoilage because bacteria, being cells, cannot live without water. Likewise the cells of the body, and the brain, do not function well without the normal concentrations of water surrounding them and in them. As you look at the neuron diagrammed to the upper right, it is important to understand that the size of the neuron is determined by how much water is inside. The large round "Soma" at the top is primarily water, simply enclosed by a membrane. In fact, most of any cell in the body is water, filled with proteins, fats, and salts. While there is a protein "skeleton", removing even part of the water will cause the cell to shrink. This in turn changes the concentration of the salts and proteins inside the cell. Since the concentration of ions is so important to the function of a neuron – due to the electrochemical gradient that is produced by charged ions – any change in concentration affects the function of the neuron.

Thus even the osmotic effects of blood glucose can alter the function of neurons. High blood glucose has additional effects that are less well understood. It appears that high concentrations of glucose can actually be toxic to neurons. This may occur because the high concentrations "saturate" the glucose transporter which allows glucose to pass from the blood to the inside of the cells, or may be due to interference by glucose at neurotransmitter receptors. While the reasons are not well understood, the effects are quite well known. Prolonged exposure to high blood glucose causes damage to neurons – particularly peripheral neurons. In this case the peripheral neurons that are most affected are the sensory neurons that convey that sense of touch to the brain. One of the first indications of diabetic peripheral neuropathy is tingling or numbness of the toes or fingers. For the reasons cited above, the sensory neurons appear to be most sensitive to high blood glucose. The onset of the symptoms varies from person to person. However, it's fairly well-established that the neuropathy develops over months to many years of high blood sugar.

At the same time, high blood glucose also affects the cells which line the inside of small blood vessels, weakening them, and predisposing them to damage. The small blood vessels of the retina in the eye are particularly sensitive, but the damage can appear to blood vessels anywhere in the body, and maybe another causative factor in peripheral neuropathy. The combination of numbness, or loss of fine touch sensation, with the potential for damage to small blood vessels, leads to frequent complications in the feet in which damage can occur but the patient not be aware of it. In this manner, diabetes can have many similar effects to leprosy, Hansen's disease, in that damage to the skin can occur without the patient detecting it, and infections and gangrene can result in considerable skin and limb damage.

Damage to small blood vessels and sensory neurons, therefore count for many of the cases of diabetic peripheral neuropathy, as well as diabetic "retinopathy"in which small blood vessels in the retina burst, scar over, and result in gradual loss of vision. In addition to the peripheral neuropathy, advanced cases can be accompanied by uncontrolled pain from damaged nerve endings, damage to the nerves around muscles and joints, and eventually the nerves which serve the internal organs. Long-term consequences of diabetic neuropathy can include damage to the nerves and muscles which serve the bladder, resulting in bladder control problems and incontinence. Damage to the nerves serving the gastrointestinal tract, in particular the esophagus, and result in gagging and swallowing problems. Very advanced cases can even involve the nerves and muscles which control the diaphragm, leading to difficulty breathing.

This cascade of problems is one reason for regular medical checkups in persons with a family history or suspicion of diabetes. Much damage can result from very small processes that accumulate over many years. Moreover, these effects occur with prolonged uncontrolled high blood glucose, and are much less likely to occur in individuals with good control of their blood sugar. Yet there is another, much less well understood, consequence of diabetes – particularly type I, insulin insufficiency diabetes. The role of insulin in the health of neurons besides control of glucose uptake is not very well known. It may very well be the case that insulin is required for the structural strength of proteins in the cells. We are certainly discovering that the effects of insulin in the brain can be quite remarkable in terms of protecting neurons from damage due to injury or chemical insult. It may very well be that without sufficient insulin circulating through the blood, cell membranes may be weakened, and show structural damage over the long-term. It's sad to say, that as much as doctors and researchers know about the disease diabetes, we still have much to learn about insulin itself.

Thus, diabetic neuropathy arises from the indirect effects of glucose on the water content of neurons, from direct effects of glucose on proteins in the cell membrane, and possibly from the lack of insulin to strengthen the cells. For diabetic, the best protection against diabetic neuropathy is control og blood glucose. In addition, diabetics should pay particular attention to tingling, numbness, joint pain, bruises, or any change in normal sensation. With proper treatment and restoration of blood glucose control further damage can be slowed or even stopped, but some permanent long-term damage may still occur. This is certainly a case where the best defense is a good offense.

---

I wish to thank my readers for their patience, I'm still dealing with a form of neuropathy myself, due to carpal tunnel syndrome. While it is getting better, it's still a bit difficult to type long blogs, and dictating them with Dragon NaturallySpeaking is taking a little bit of getting used to.

In addition, the day job has taken a few "interesting" turns, one of which will require me to travel next week, also interfering with my progress in posting these blocks. Please bear with me, there is much more content still to come.

Until next time, take care of your brain, your neurons, and your blood sugar!

Monday, March 19, 2012

[updated 4/2/12]
Carpal tunnel syndrome is a catchall term for repetitive motion injuries that involve the wrists. Repeated motions around a joint: wrist, knees, ankles, etc. without appropriate support or care to prevent injury can cause inflammation. The constant movement of muscles and tendons around the joint causes wear, small tears, stretching, and eventually causes the tissues to swell and become painful.

When this happens at the wrist, the swelling can cause one of two things, pain which can be treated by ice and anti-inflammatory drugs, and pressure on the ulnar nerve, again causing pain as well as numbness of the fingers. The numbness occurs because the neurons that make up the nerve bundle of the ulnar median nerve (although ulnar and/or radian nerve can be involved in advanced cases) - which passes through the "carpal tunnel" inside the wrist - are compressed and the compression causes electrical activity within the neurons. Since neurons that make up the long nerves from spinal cord to the periphery are not designed for constant activity, the activity caused by compression "fatigues" the neurons, and they no longer transmit sensory information the way they should. The result is feeling of pain in the hand and numbness of the fingertips in particular the thumb and first two fingers. Another characteristic of carpal tunnel syndrome numbness is that the lack of sensation extends to the third or "ring" finger, but only partially. Last half of the finger appears to have normal sensation, while the half closest to the thumb is numb, just like the adjacent first and second finger. What this means for writer is pain and numbness as they try to type particularly if the risks are not appropriately supported on a desk or on a keyboard. The numbness makes it very difficult to touch type, and the pain tends to slow down any typist whether they touch type or hunt and peck.

[As a tie-in to other posts in this series, diabetics show increased susceptibility to Carpal Tunnel Syndrome.]

This is a rather long-winded way to notify readers that I am having some difficulties with carpal tunnel syndrome, particularly in my left wrist with numbness in the fingers of the left hand; but also with some pain in the right wrist. This is usually transitory passing within a couple weeks, and often occurs soon after I take plane trips such as I did approximately 2 weeks ago. What this means for this blog is that to write these columns I am now dictating using Dragon NaturallySpeaking software. It works fairly well but is a slow process, because I have to frequently stop and correct technical terms. For this reason I'm a little bit behind in the planned blog posts for this week. I'm planning a follow-up post on diabetes and the brain to discuss the peripheral neuropathy that occurs in advanced cases. I also intend to finish the Guide sections on neural prosthetics and bionics before moving on to the topics that have been suggested by readers. I still have plans to complete these blogs this week and post them as time allows. However, it will take time to do so and I may get a little bit behind in the posting schedule.

Please bear with me, and I will post new content for The LabRats' Guide to the Brain as time and my wrists permit.

Wednesday, March 14, 2012

[Apologies for typing and phrasing problems. I am suffering from very uncomfortable carpal tunnel syndrome this week. This blog was dictated using Dragon Naturally Speaking.]

Today's blog is a bonus one that I hadn't intended to write, but recent family events have prompted me to talk about effects of diabetes on the brain. I'll start with a description of what exactly the disease we call diabetes consists of,then returned to the idea of what diabetes has to do with brain function. But I'll give you little hint, neurons and the support cells of the brain cannot make their own glucose from stored molecules; they are completely dependent on the blood supply for delivery of glucose.

Diabetes mellitus is the scientific name for diseases involving the production of insulin, which is necessary for transporting glucose into the cells of the body. There is another disease, diabetes insipidus, which is as many similar characteristics including excessive urination, but is essentially a kidney disease and does not involve insulin. Type I diabetes results when the pancreas cannot produce insulin. Type II diabetes results when the cells of the body don't respond to insulin. In both cases the body is unable to transport high concentrations of glucose from the blood into the cells that need it.

Insulin is produced in the pancreas by cells called Islets of Langerhans. From before birth these cells produce insulin whenever blood sugar (blood glucose) is elevated. Blood glucose increases after eating a meal, increases after exercise in order to replace the glucose used by the muscles, and it is increased during fever fighting disease. Most of the glucose in our body comes from the food we eat, and excess glucose is broken down then converted to longchain's of carbon known as fatty acids. Fatty acids together with triglycerides form the facts that are deposited in the adipose cells and forms the fat tissue of the body. When the body needs this extra energy, it breaks down fats and uses a process called gluconeogenesis to create glucose. Small amounts of glucose can also be stored as a complex molecule called glycogen, and most glycogen storage is in muscles that use it during exertion, and in the liver. Since alcohol contains a lot of glucose molecules one of the characteristics of advanced alcohol poisoning or alcoholism is extensive fat and glycogen deposits and the liver. Nutrients including glucose are absorbed into the blood stream from the food we eat, then passes through the liver for processing of the molecules and eventually ends up circulating in the blood, stored as glycogen in liver and muscles, or stored as fat in the liver and adipose tissue.

Glucose as a molecule however, it's too big to pass across the membrane into the cells of the body. A specialized transporter molecule latches onto the glucose and transported into cells. This transporter molecule requires insulin in order to activate, and if there is not enough insulin, or if the transporter and cells becoming sensitive to insulin, then the glucose builds up in the blood. Too much glucose in the blood means (A) that glucose is not getting inside the cells that need it, (B) that the glucose will remain in the blood until it is removed by other means. Usually this means that the kidneys have to filter the glucose out of the blood and into the urine, causing damage to the filtering cells of the kidney and showing up in urine tests. Too much glucose in the blood has another effect similar to too much salt in water, it increases the "osmotic pressure" of the blood and causes water to be drawn out of cells to dilute the high glucose concentration of the blood.

And thus we get to the effects of diabetes in the brain: Glucose is necessary for the function of brain cells, which fortunately are not as dependent on insulin for the uptake of glucose. While not all of the effects of too much or too little insulin in the brain are known, too much glucose in the blood "dehydrates" brain cells via osmotic effects. A person who enters a diabetic coma, from too much glucose and too little insulin, is essentially suffering from a severe case of dehydration of the brain cells. In fact, dehydration in general can be associated with disruptions in the insulin and glucose balance in the blood.

Other factors involved come from the fact that without insulin, the cells of the body send signals for more glucose. The liver starts breaking down fats (yielding a lot of methyl and ethyl ketone byproducts) and cells produce a lot of lactic acid from alternate energy molecules. The resulting "diabetic ketoacidosis" can also be associated with weakness and coma since the acid and ketone molecules disrupt normal neurotransmitter and glucose uptake mechanisms int he brain. So uncontrolled diabetes can cause the "double whammy" effect on the brain both from osmotic and metabolic causes.

There is another role for insulin in the brain, besides the glucose transporter (which, as stated above, is different in the brain and does not require insulin). Many recent studies have shown that there are insulin receptors on neurons and glial (support) cells in brain, and that some specialized cells might produce very small amounts of insulin. Insulin does not easily cross the blood brain barrier, but may be actively transported and can reach the brain through the nasal mucosa. Insulin in the brain appears to improve memory, alertness, attention, and it acts as a neuroprotectant in case of brain injury.

There are many myths about diabetes - the first being that "juvenile diabetes" (Type I, insulin insufficiency) occurs only in the young, and you're either born with it or not. The second is that adult-onset diabetes (Type II, insulin insensitivity) is caused by overeating. The truth is that either disease can occur at just about any age, and comes not from diet, but from the body's metabolism. Getting fat doesn't cause Type II diabetes, but it does likely indicate that the body is already insensitive to insulin (thus carbohydrates in the diet are turned into fat and not metabolized). A given person can also convert from Type II to Type I very suddenly: a long period of uncontrolled Type II diabetes requires increased insulin production by the pancreas, and the over-stimulation can result in an abrupt "crash" if those same cells become diseased or inactive. There is a large genetic component, but we still don't really know what causes islet cells in the pancreas to die or not produce insulin, but there are some intriguing gene and stem cell therapies that should start becoming available in the next 5 years.

So, contrary to some popular opinion that Type II diabetes is a gimmick to sell more pharmaceuticals, it is a real problem, with real consequences both to the body and to the brain.

Monday, March 12, 2012

Real Life has intervened and I am unable to write the Stellarcon Afteraction Report or continue Guide posts until at least Wednesday.

So, for my patient readers, here's a wee short story:

Lower Education

A short story by Tedd Roberts

No matter how hard I tried, it
just wasn't possible to block out the sounds of a 13 year old boy arriving home
from school.

"Mom, I think my teacher is
an Alien."

I was working in my home office, but
Will’s voice carried throughout the whole house. It certainly got my
attention.I turned down the music in
time to hear my wife’s quieter voice correct him: "Of course William,
there are lots of immigrants teaching in our schools."

"No Mom, an illegal alien."

"William, that’s not
nice. I’m sure there are no undocumented workers at your school."

"Mo-om, I mean a SPACE alien,
like Mr. Spock, but not so nice."

I had decided it was time for a
break. I'd come home from the lab to write my research grant application
and had gotten a lot of work done.I had
the rest of the weekend to do the proof-reading, so I could afford some rest.
As I entered the kitchen, I asked: "What makes you say that, Will-o?"

"Well, Mr. O’Connor handed
out the test papers and told us he didn’t want to see us looking around at
other kid’s papers. Then he went to his cabinet and was looking in some
sort of mirror and he just kinda ‘fuzzed’."

"Fuzzed?"

"Yeah, like on TV, whenever
they want to imitate a hologram, it looks kind of 3-D, but then it fuzzes, and
wiggles around, then snaps back into focus."

"And just what were you
doing looking around? Especially since he told you not to."

"He’s just gotten creepy,
Dad. I couldn’t help it."

"So did he see you?"

"Uh, yeah, I guess
so." Will reached into his pocket and pulled out a piece of blue
paper that had been folded down to about an inch on a side. "I’m
s’posed to give this to you."

I unfolded the paper into a
standard letter-sized page and read the notice that "William Reynolds
received a failing grade on his Algebra test because of cheating" and
would I please meet with the teacher and vice-principal on Monday.

*****

Monday wasn’t a great day.
The grant application had to be submitted around noon, and there was a lot to
be done. Finally the Sponsored Research Office and I had the application
completed and submitted. It looked like I would make it to the 2 o’clock
meeting after all.

Instead of being ushered into the
Vice-Principal’s office, I was led to a small conference room filled with not
just the VP and Algebra teacher, but all of William’s core curriculum teachers,
and the district assistant superintendant. "Professor Reynolds,"
began the VP, "we have a problem with William."

"William is insolent,"
said the English teacher.

"He’s a smart-ass,"
corrected the Science teacher, "he argues with all of the students and
rejects the accepted State Science Curriculum."

"He has no appreciation of
the process for completing his Social Studies projects."

"Mr. Reynolds," hissed
the assistant superintendant in a low voice.

"That’s Doctor Reynolds,
Sir."

"Yesssss, Dr. Reynolds.
You sssssee, this program is for highly academically gifted
ssssstudentsssss. Your ssssson is impeding their progresssss. He
must leave the program. I will leave you" he pointed to the VP
"to sssssettle thisssss."

The teachers left me alone with
the VP. "Mr. Judge, Will's a good kid, he’s gotten good grades until
now. "

"Dr. Reynolds, I
sympathize. I have enjoyed having both of your sons in this school, but I
can’t ignore the teacher evaluations. I have reports here - William
refuses to show his work in Math, claims he can calculate the answer in his
head. He argued with the Science teacher and students over scientific
evidence regarding pesticide and fluorocarbon bans. He called the Social
Studies teacher a Socialist, and refused to complete an English project making
African Tribal Masks."

"Wait a minute – were his
answers wrong? Did he show proper literature citations? The
Social Studies teacher is a Socialist, she gave him a failing grade on
his Constitution paper about the Second Amendment, and what do African Tribal
Masks have to do with English grammar and American Literature?"

"That’s irrelevant Dr. Reynolds.
Modern education is about the processnot the outcome.
I’m afraid they are right. William must move to a different school. I
suggest the military academy in Oak Ridge."

*****

The day got worse when Bobby
arrived home unexpectedly from college.

"Dad, I’m dropping out.
The neanderthals in the Biology department have decided we can’t even do
dissections any more. I can’t take it, I’d rather write Science
Fiction."

But it was all overshadowed by the
news that night. It had happened. There was intelligent life out
there in the Universe. Communications had been established. The
first envoy would be here in a couple months and they wanted to visit Earth’s
scientific and educational institutions to see if we were eligible for
membership in their galactic society.

That would show the
educators who was right. We’d survive. I got William transferred to
a private school and Bob was enrolled in an on-line degree program. Let
him get an associates and work for a few years.

We were fortunate to be selected
for one of the scientific tours for our new friends, The Hysst. Our
neural computing facility, the prosthetics group, and the tissue engineering
institute had caught their attention, so we had to prepare a dog and pony show
for the Ambassador and a group of scientific advisors.

It took about six months to set up
the visit. Toward the end, I corresponded pretty regularly with my
counterpart Tar-Yrl, who had the Hysst equivalent of a doctorate in neural
medicine. Near as I could figure out, he was a professor at a major
research institute and had been attached to the Embassy to help evaluate
Earth’s scientific progress. Once the tour had finished in our area I
found that I had a few minutes alone with Tar. I felt I knew him well
enough to talk about subjects other than our immediate scientific interests, so
I told him my concerns about educating our children to be productive citizens
of galactic society.

I was shocked by his
reaction. I realize I shouldn’t have made assumptions about an alien
race, but I was pretty sure that grimace was their equivalent of a smile and
the head nod meant agreement. Tar seemed to be approving of the
teachers!

I couldn’t believe it, so I
asked: "Tar how can you approve of a system that teaches kids to be
mediocre and ignore real education?" But as I listened to his answer
it hit me where I'd heard that type of voice before.

"Friend Reynoldsssss.
You misssssunderssssstand. We don’t want you to be educated."

Friday, March 9, 2012

This weekend I am at Stellarcon science fiction convention in High Point. I will try to have a convetion report this next week once The Guide posts on neuromuscular diseases are completed. In the interim, here is a recent musing on friendship:

CIRCLES.

Some years back I was in conversation with my wife and
referred to a conversation I had with a friend.
My wife interrupted me and said "You call everyone a 'friend' but
you barely know this person – is he really a 'friend,' or just an
acquaintance?" While stung by the
comment, I realized that what she was saying was true, and I tended to call all
acquaintances 'friends' no matter the degree of relationship. The proliferation of Facebook 'Friends' falls
in this same category, although Facebook does allow a distinction between
simple 'Friends,' 'Close Friends,' 'Acquaintances,' and 'Friends of
Friends.' This intriguing notion of
cataloging and classifying degrees of friendship – as well as some recent
personal developments in which my circle of contacts has expanded in
interesting directions – has prompted a re-evaluation of who I call 'friend'
and how I mentally tag and classify my acquaintances.

So, what qualifies 'friendship?' We have family friends, work friends, school
friends, neighborhood friends, childhood friends, and correspondence friends
(formerly 'pen pals' but now typically internet friends). We start out in life with two circles –
family, and the friends of other family members. We often tag such family friends as being as
close as family – particularly in the case of friends of our parents whom we
call 'Aunt Mary' or 'Uncle Bill' despite no blood relationship. Frankly, as we learn later in life, blood
relationship does not guarantee friendship, nor does the lack mean a person
doesn't feel as close to you as family. As
we enter school and expand our circles to include classmates and the kids we
play with in the neighborhood, we develop 'Best Friends' and playmates. The common question of childhood – "Will
you be my friend?" – shows that what we want most from a friend is
companionship and recognition that we are worth playing with. Childhood friends are among the closest
relationships we feel at any age, even though we intellectually know (as adults)
that there are many closer (and more distant) degrees of friendship. If we are lucky, we retain some of our
childhood friends into adulthood, we certainly carry their memory with us for
the rest of our lives. I still think
fondly of Louie and Steve, even though I have not seen either of them in more
than 40 years.

Into high-school and college years, we further expand our
circles to include those with whom we took courses, studied, shared a dorm
room, or partied with. In this stage we
also carve out a special niche for boyfriends/girlfriends, but essentially,
'school mates' are folks with whom we shared formative experiences, common
intellectual – or less than intellectual – pursuits. Our school friends begin to form the new
circle that we will call 'peers' and again, if we are lucky, we will form
friendships that last many years. Often
we lose touch with 'school mates' after several years; but rekindling a
friendship, as I have done with someone from my college years and had not seen
in 30 years, can result in that rarest of friendships, the true 'close friend'
with whom we can share our life experiences.

As we leave college and enter the workforce, we enter a
circle of ambiguous levels of friendship.
As a pure employee, we may form friendships with co-workers and even
bosses, but the boss-employee friendship is rarely a true friendship unless it
is reinforced by other connections outside of the workplace. As one moves up to management levels, the
boss-employee relationship reverses. I
myself am in a position with only a couple layers of management above me, but
several layers of employees below. While
I am on friendly terms with my technicians, only one and two are 'friends' and
those primarily due to long-standing relationships (over 25 years in one case)
that preceded the boss-employee relationship.
Likewise, I am on friendly terms with my boss and his boss, but calling
it a close friendship is questionable, despite the 30 years we have worked
together.

More likely at this point, we have 'colleagues' and
'peers.' Like family, we don't have to
like them, but we are stuck with them. A
number of my colleagues are in fact old college friends, and we spend time
together, having a beer or coffee whenever we are in the same town. Some may even approach the realm of 'close
friend,' but most remain in that circle of colleagues with whom we interact daily, but do not share
the details of daily life.

By this point in life, with growing families, renewed
familial ties and an expanding circle of connections due to neighborhood and
mutual activities, we develop an extensive network of acquaintances. Here is where the distinctions start to
blur: I am on good terms with my sister
– is she a 'friend?' A 'close friend?' or still simply family? I have been a Boy Scout adult leader – are
those fellow adults 'friends' or 'acquaintances?' Certainly I enjoy their
company and we have many shared experiences – but would they be willing to come
babysit me when I've had major surgery and am not allowed to be alone? This, I believe is the key to friendship –
'friends' are those with whom we share life experiences – we have common
ground, we are interested in their life, and they are interested in ours. A close friend is willing to put that all on
the line to help dig fence post holes in the rain, to keep you company in the
hospital, to be there when you are worried, or sick, or grieving. It is in adulthood that we realize who our
friends are, and who is merely an acquaintance.

But what of the
internet? Facebook? Online communities?
I have many 'online friends' some of whom are willing to listen as I
pour out my feelings and to whom I listen in return. Are they any less 'friends' for the fact that
I do not spend time with them in person?
Such a long-distance correspondence relationship used to be known as a
'pen pal' and many such correspondences led to long-lasting friendships,
enabled long-distance romances and kept families in touch through war and
troubled financial times. This is no
less true today, even though the medium has become faster and even allows
face-to-face as well as written and spoken communication. Thus within our online communities we can
apply the same categorization from 'close friends,' to 'acquaintances.'

I find this particularly fascinating these days as my circle
of 'friends' expands through contacts I have made via Facebook, Baen's Bar, and
simply emailing a person with whom I wish to converse. One connection has evolved from acquaintance
to almost-family with the result that a person I met online only four years
ago, now has multiple avenues of interaction with me, my parents, my sister,
etc. Those interactions are no longer
confined online, but occur by phone, in person, and at each others' homes. In another example, I have reconnected with a
classmate from college that I knew as the friend of a friend, but we now
connect online almost daily and speak on the phone several times per week.

With new friends comes new acquaintances as they and I
become 'friends of friends' and work on developing yet another circle of
connections. Thanks to some of my
friends, I now count several authors and journalists among both my friends
and my acquaintances. The more I
interact, the more these people progress through the multitude of circles with
which we surround ourselves. The old
joke about "six degrees of separation" is true. Even a passing, distant acquaintance becomes
our connection to another. From any
friend, I can count an acquaintance who has another acquaintance who has a
friend...

Wednesday, March 7, 2012

The planned topics for The Lab Rats' Guide to the Brain are beginning to wind down. Over the course of a year, I have blogged sections of the Guide that were already written, or have been planned and written on-the-spot for the Guide.

Currently, the only disease/disorder section still planned for the Guide is on Fibromyalgia. As for additional sections that I thought would be of interest to readers, I have:

* Blindness, Deafness and modern prosthetics

* Bionics

So, to continue this blog after these topics are complete, I am open to suggestions for content. If I have content of interest to readers, I will continue to expand the original intent of The Guide. Suggestions that I received last week on Facebook include:

* Mirror Neurons - a very interesting topic, and I will do some research and add this to the list.

* Travis S. Taylor's theories of the quantum-computer mind - This will be interesting, because I disagree with Dr. Taylor, but I think there is some validity to some of his concepts. I will pick up a copy of his "The Science Behind the Secret" and treat this as a combination book review and Guide entry on the ideas. I would love to debate Travis on the topic at some future time, and this may be a good way to introduce the topic.

* Multiple Personality - not being a psychologist, this is a difficult subject, but one approach for me would be to talk about the neurophysiological evidence for "personality" in general and to examine the differing physiological signs that have been reported in clinical cases of personality disorder.

* Up and coming psychoactive drugs - actually a very interesting topic, and it will be good for me to research as well as to distill down to basics for this audience. I will have to alter the premise a bit, though, and focus on what is known and future directions for drugs as therapies and the risks of abuse.

* Following up on the idea of personalities, a look at how writers can create personalities without taking on characteristics of those personalities.

These are all great suggestions, and I will try to incorporate them in the coming weeks. Please send more! I will also try to keep up with some more book reviews, convention reports and commentary on science in the news.

Monday, March 5, 2012

Q: What do theoretical physics and the New York Yankees baseball team have in common?
A: Amyotrophic Lateral Sclerosis... the disease that has confined physicist Stephen Hawking to a wheel chair and voice synthesizer, and which took the life of "The Iron Horse," baseball player Lou Gehrig.

ALS is another neuromuscular disease, and the last in this series of Guide posts. Like Multiple Sclerosis, it is a disease that causes wasting and death of the long neurons leading from brain to muscles, but unlike MS, is confined only to those muscle-control neurons, and does not affect the sensory nerves from body to brain. The gradual degeneration of muscle control leads to the most unfortunate side effect of ALS - a person's perfectly healthy brain locked inside their own body.

The symptoms of ALS usually start out with muscle weakness, as experienced by 1930's baseball star Lou Gehrig. Prior to onset of his disease, he was a powerhouse batter, with a consistent batting average of around .350, over 500 runs-batted-in per year for three years in a row, and records in hits, runs and bases for most of his 17 years and 2,130 consecutive baseball games. In fact, if not for teammate George Herman "Babe" Ruth, Gehrig would have even held home-run records for many of those same years (1923-1939). However, midway through the 1938 season, it was obvious that his strength and stamina were failing. In 1939, as his coordination and strength failed, he went to the Mayo Clinic in Rochester, Minnesota for diagnosis - amyotrophic lateral sclerosis - and received the grim prognosis for increasing paralysis and death within three years. Sure enough, ALS took the life of the self-proclaimed "Luckiest Man on the Face of the Earth" in 1941.

In stark contrast, Stephen Hawking first noticed loss of balance and coordination in his 20's and received the diagnosis of an ALS-like syndrome in 1963 at age 21. The progressive paralysis has confined Hawking to a wheelchair since his mid 20's, and has been unable to move himself since 1974 (age 32). An emergency tracheotomy due to pneumonia took what remained of his voice in 1985, but he has used a speech synthesizer for interaction since before synthesizers became "established" technology. Today he presents prerecorded talks, using the synthesizer, and can even answer questions using facial muscle "twitches" to control a computer, although the process of answering even a single question can take 5-10 minutes. Hawking is still active in theoretical physics, revealing how the sensory and mental facilities remain intact even as the muscle control of the body is lost.

There is currently some dispute whether Hawking's 50+ year survival with ALS means the disease is actually classic amyotrophic lateral sclerosis. Classically, ALS symptoms do not develop in people younger than 50. Gehrig was diagnosed at 35, Hawking at 21. Gehrig exhibited the typical 3-5 year survival, but Hawking has managed to hold on - perhaps by sheer power of will and the support of some of the most technically advanced gadgets (and friends) in the world. As with the other diseases and disorders covered in this series, there is no known cure, the source is unknown, and only about 10% of the cases appear to be genetically linked. Essentially the disease results in atrophy (wasting) of motor neurons and muscles. Loss of the ability to swallow is common in early cases, and even the ability to breathe voluntarily is compromised in advanced cases. Initial treatment is usually with riluzole, which reduces over-activation of neurons by the neurotransmitter glutamate, and may play a role in prevent "excitotoxicity" when injured neurons are over-stimulated. The drug can prolong the early stages of the disease and particularly delay the onset of breathing difficulties requiring artificial ventilation. Other treatments generally focus on controlling muscle spasms and easing swallowing and breathing difficulties.

The sad news of the neuromuscular diseases is that in most cases we don't know how or why they are caused, how they can be treated, or what we can do to ease the quality of life of patients who all-too-often are locked inside their own failing bodies.

Perhaps what we need is for some young scientist - perhaps inspired by science fiction - to discover a cure.

Saturday, March 3, 2012

The Muscular Dystrophy Association lists more than forty diseases under the umbrella term of Muscular Dystrophy (http://www.mdausa.org/disease/). Notably for this series, they include Myasthenia Gravis - MG, as discussed in the previous blog, and Amyotrphic Lateral Sclerosis - ALS, which we will cover in the next installment of The Lab Rats' Guide to the Brain. Notably absent, despite the fact that it is a neuromuscular disease, is Multiple Sclerosis - MS, perhaps because it has its own foundation, fundraising and research network.

The catch-all term Muscular Dystrophy, or MD, refers primarily to diseases of the muscles, typically not exclusively autoimmune diseases like MS and MG, but frequently genetic diseases that arise from faulty or missing genes. MD specifically refers to muscle weakness, and can significantly include wasting or atrophy of muscles. Also, unlike MS and MG, which are generalized diseases that affect all muscle and neuron sites in the body, the various subtypes of MD can include only specific muscle groups, with the consequence that weakened muscles on one side of a bone or joint cannot counter the contraction of normal muscles on the other side, resulting in deformities around the spine and joints.

The most notable of the dystrophies "Duchenne's Muscular Dystrophy" and the less severe variant "Becker's Muscular Dystrophy" result from the genetic lack of "dystrophin," a structural protein in muscle cells. With low levels of protein, or abnormal protein, the muscles cannot grow normally, accompanied by weakness of the muscles of voluntary movement, such as walking, particularly since the muscles of the legs and hips often show the first signs of the disease. Duchenne's appears in early childhood, and eventually affects heart and breathing muscles, such that survival past 30 years of age is rare. Becker's typically appears in late adolescence and early adulthood, and a near-normal lifespan is possible. Given that both diseases affect the same protein, it is not surprising that they have a common cause - a faulty gene on the X chromosome. The disease is "sex-linked recessive" most common in males, who receive their faulty X chromosome from a typically non-diseased mother. The disease is rare in females, and would likely co-occur with other genetic disorders, since the likelihood of a female with two faulty X chromosomes being able to have children is highly unlikely.

Other dystrophies such as Facioscapulohumeral Muscular Dystrophy (FMD) affect men and women alike. FMD is caused by a missing gene on the fourth chromosome, and affects mostly upper body muscles, rather than lower body muscles such as Duchenne's and Becker's dystrophies. FMD is quite often accompanied by loss of control of facial and neck muscles, preventing facial expression and causing sloped shoulders, drooping eyelids, impaired speech, and inability to whistle or "purse" the lips.

There are also metabolic causes of of MD. Myotonia Congenita is a another genetic disease (present from birth, hence the name from the language root "congenital") of the ion channels in muscle. Abnormal chloride channels in muscle prevent chloride from quickly entering muscle cells after contraction. During the process of contraction, positively charged sodium and calcium ions enter the muscle cell, much the same as during an action potential in a neuron. Potassium typically flows out and chloride into the cells to "repolarize" or returning to the normal negative resting voltage. With defective chloride channels, the muscles can relax only very slowly, resulting in rigidity, slow movement, difficulty in swallowing. Fortunately, continued movement relaxes muscles, and movement becomes easier. The disease is well treated with anesthetic-like muscle relaxants, and symptoms can improve as the patient ages.

Again, with over forty diseases and disorders in this category, it is difficult to do more than sample the types of muscular dystrophies. For more information, I highly suggest the MD page at PubMed Health (http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002172/) as a starting point, and the excellent listing of diseases at the MDA site (http://www.mdausa.org/disease/) for a clickable list of diseases, symptoms, causes and treatments. For writers, the illustrations and personal stories can assist with character development if you choose to use one of these diseases in your writing. For patients and families, there are useful links to medical information, support groups and physician referrals.

After a short break for the Stellarcon science fiction convention, we will conclude the series on neuromuscular diseases with ALS - the disease that cut down "The Pride of the Yankees", baseball player Lou Gehrig, in his prime - but has failed to stop the intellect of physicist Stephen Hawking after nearly 50 years.

Thursday, March 1, 2012

Welcome to Part 2, and the second of the "Three M's" - Myasthenia Gravis.

Like Multiple Sclerosis (MS), Myasthenia Gravis (MG) is an autoimmune disease - meaning that the body's immune system attacks its own cells, thus causing the disease. It tends to affect younger women and older men. Unlike MS, in which the target is the insulation of neurons, the target in MG is the junction between neurons and muscles.

Copyright Alila Sao Mai, 2012
Used under license from Shutterstock.com

The diagram at the right shows a typical junction between two neurons. The "axon" of one neurons acts as the "sending" terminal for information. Within this "presynaptic" neuron, information is represented as the pattern, frequency and spread of electrical action potentials, much like Morse Code, FM radio signals or computer serial communications. However, since the electrical signals cannot be conducted directly to target neurons (without loss) the signal must be converted to a chemical one at the "synapse" where the sending and receiving neurons touch. Each action potential entering the axon terminal results in release of a small amount of chemical neurotransmitter. That neurotransmitter diffuses across to the "receptors" on the "post-synaptic" receiving neuron. The receptors are proteins in the cell membrane that allow charged ions into the postsynaptic neuron. Thus when the neurotransmitter activates the receptors, it can cause a copy of the electrochemical action potential in the receiving neuron, allowing transmission to the next neuron, and the next...

At the muscle, a similar synapse can be found in which a motor neuron releases neurotransmitter (always acetylcholine) onto receptors on the postsynaptic muscle cell. We call this type of synapse a "neuromuscular junction." The receptors on the muscle cells serve two functions - (1) to allow muscle action potentials to occur, and (2) to allow calcium into the muscle cells in response to positive voltages. The muscle action potential ensures that a small amount of positive electrical voltage (about 70 milliVolts) spreads all throughout the muscle. The positive voltage opens ion channels for calcium, allowing it into the muscle cells. Within the cells, calcium is responsible for the actual contraction of the muscle. [I highly recommend the video at left (along with the New Zealand accent) for a pretty decent explanation of muscle contraction.]

In Myasthenia Gravis, the autoimmune reaction results from the body making antibodies to the acetylcholine receptors on the muscle. Symptoms of MG can be similar to MS or muscular dystrophy, except that the symptoms are confined to the muscles. Tests of muscle conduction (the ability to transmit electrical impulses throughout the muscle) and nerve conduction will be normal, but the transfer of signals from nerve to muscle will be delayed or impaired. Aside from simple muscle weakness, MG can result in breathing, swallowing or chewing difficulty, paralysis, fatigue, difficulty holding the head or body upright, or problems with double vision, focusing the eyes or drooping eyelid (typically the first symptom noticed). The doctor may also run tests for presence of the acetylcholine receptor antibodies.

Like MS, the course of the disease can be slowed with immune suppressants, and specific support of the muscle function can be provided by drugs that prolong acetylcholine action at the neuromuscular junction (such as neostigmine or physostigmine which inhibit the breakdown of acetylcholine). Caution must be exercised, however, since too much acetylcholine causes what medical students learn as "S.L.U.D.E. syndrome" (Salivation - drooling, Lacrimation - tearing of the eyes, Urination - full bladder or loss of bladder control, Defecation - loss of sphincter control or diarrhea, Emesis - nausea and vomiting), thus acetylcholine support therapies must be very carefully monitored.

MG can cause medical crisis when the muscle that control breathing are involved. Typical therapy involves "plasmapheresis" in which the blood is filtered to remove the excess antibody to the acetylcholine receptor. Unfortunately, plasmapheresis removes all antibodies, so the patient must avoid risk of infection. There is some indication that the thymus, an immune-system gland in the lower neck, may be involved in MG, and surgical thymectomy or removal of the thymus can provide some relief.

Like MS, there is no cure for MG. Once the synapses and neuromuscular junctions are damaged, they can become scarred and will not recover. However immunosuppressant therapy, thymectomy, acetylcholine therapies and lifestyle changes can provide a normal lifespan with close control of symptoms. For those wanting more specific information, such as diagnosis and treatment, as always, I defer to the excellent work at PubMed Health: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001731/.

In the next segment, we will discuss the remaining of the "Three M's" - Muscular Dystrophy - which is a catch-all term for many neuromuscular diseases, then conclude this topic with a discussion of Amyotrophic Lateral Sclerosis - ALS or Lou Gehrig's Disease.